Gelation‐Induced Enhanced Fluorescence Emission from Organogels of Salicylanilide‐Containing Compounds Exhibiting Excited‐State Intramolecular Proton Transfer: Synthesis and Self‐Assembly |
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| Authors: | Manoj?Kumar Nayak Dr Byung‐Hwa Kim Ji?Eon Kwon Sanghyuk Park Dr Jangwon Seo Dr Jong?Won Chung Soo?Young Park Prof |
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| Institution: | 1. Current address: Department of Chemistry, Texas A&M University at Qatar, PO Box 23874, Doha (Qatar);2. Center for Supramolecular Optoelectronic Materials and WCU Hybrid Materials Program, Department of Materials Science and Engineering, Seoul National University, ENG 445, San 56‐1, Shillim‐dong, Kwanak‐ku, Seoul 151‐744 (Korea), Fax: (+82)?2‐886‐8331 |
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| Abstract: | Self‐assembly structure, stability, hydrogen‐bonding interaction, and optical properties of a new class of low molecular weight organogelators (LMOGs) formed by salicylanilides 3 and 4 have been investigated by field‐emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), UV/Vis absorption and photoluminescence, as well as theoretical studies by DFT and semiempirical calculations with CI (AM1/PECI=8) methods. It was found that salicylanilides form gels in nonpolar solvents due to π‐stacking interaction complemented by the presence of both inter‐ and intramolecular hydrogen bonding. The supramolecular arrangement in these organogels predicted by XRD shows lamellar and hexagonal columnar structures for gelators 3 and 4 , respectively. Of particular interest is the observation of significant fluorescence enhancement accompanying gelation, which was ascribed to the formation of J‐aggregates and inhibition of intramolecular rotation in the gel state. |
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| Keywords: | fluorescence gels proton transfer salicylanilides self‐assembly |
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